In themes/default/profile.template
Find before
// Are there any custom profile fields - if so print them!
And remove
if (allowedTo('smfstore_userstore') == true || allowedTo('smfstore_manage') == true)
{
echo '
<dl>';
echo '
<dt>
<strong>', $txt['smfstore_paypal_address'], '</strong><br />
<span class="smalltext"></span>
</dt>
<dd>
<input type="text" name="default_options[store_storepaypal]" size="50" value="', $context['member']['options']['store_storepaypal'], '" />
</dd>';
echo '
</dl>';
}